Water cooled outboard mounted marine propulsion device with corrosion prevention



July 31, 1962 WATER Filed Aug.- 5, 1960 E. C. KIEKHAEFER COOLED OUTBOARD MOUNTED MARINE PROPULSION DEVICE WITH CORROSION PREVENTION 2 Sheets-Sheet l INVENTOR. Elmer C. Kiekhaefer BY flndrus fisfarlge Wftornegs July 31, 1962 E. c. KIEKH FER 3,046,930

WATER COOLED OUTBOARD MOUN MAR PROPULSION DEVICE WITH CORROSION PREV ION 2 Sheets-Sheet 2 Filed Aug. 5, 1960 INVENTOR.

Elmer GKie/[haefer BY Andrus Star/(e Wffarneys United States Patent 3,046,930 WATER COOLED 0UT3OARD MOUNTED MARINE PROPULSION DEVICE WITH CORROSION PRE- VENTION Elmer Carl Kielthaefer, Cedar-burg, Wis., assignor, by

mesne assignments, to Kiekhaefer Corporation, Chicago, 111., a corporation of Delaware Filed Aug. 5, 1960, Ser. No. 47,816 3 Claims. (Cl. 115-17) This invention relates to a water-cooled outboard marine propulsion device with corrosion prevention.

Outboard motors are generally provided with a water cooling system for the engine. These systems have included a water jacket or the like which surrounds the engine, and which connects downwardly through suitable passages in the drive shaft housing to a water inlet opening disposed beneath water level.

It has been found that the size of any water inlet opening must be restricted to prevent entry of small fish or other foreign matter into the cooling system. At the same time it has been discovered that corrosion of the inlet structure usually occurs, due to the galvanic action of sea water and the like. The galvanic corrosion, and accompanying buildup of mineral and other deposits, causes a gradual clogging of the inlet. This results in undesirable engine overheating.

The present invention solves the foregoing problem, and provides means for prevention of corrosion of the water inlet.

The accompanying drawings illustrate the best mode presently contemplated by the inventor for carrying out the invention.

In the drawings:

FIGURE 1 is a side elevation of an outboard motor constructed in accordance with the invention;

FIG. 2 is an enlarged fragmentary side elevation of the lower portion of the motor, with parts broken away and in section;

FIG. 3 is a view taken on line 33 of FIG. 2, showing the inlet configuration;

FIG. 4 is a horizontal section of the fin, taken on line 44 of FIG. 2; and

FIG. 5 is a view similar to FIG. 4, showing another embodiment of the fin.

As shown in FIGURE 1 of the drawings, the invention is adapted for use on an outboard motor 1 which comprises a power head 2, a drive shaft housing 3 extending downwardly from the head, and a lower gear housing 4 which is secured to housing 3 and which carries a propeller 5.

The housings 3 and 4 enclose the usual connections for driving propeller 5 from power head 1.

For the purpose of water cooling the engine, a Water intake member 6 is disposed slightly above and rearwardly of propeller 5. A plurality of relatively small inlet openings 7 are disposed in member 6, with the openings connecting through passageways extending upwardly to the power head is any well-known manner.

Member 6 may be an integral part of the motor housing, or may be secured thereto, as by bolts 8. As shown, member 6 has a fiat horizontal upper portion, and tapers downwardly in a rearwardly direction to form a generally concave surface which faces forwardly and which contains openings 7.

The openings 7 form a grillwork inlet through which water is forced to cool the engine as the mounted unit moves forward in the water.

It has been found that sea and some other waters have "Ice 2 a substantial corrosive effect on the intake openings, and in time the deposits of minerals and salts seriously impair the water cooling function.

To prevent such eifects, an anode shown here in the form of a vertical fin 9 is provided with the fin having a projection 10 which fits into a slot 11 in the rear edge I of member 6, and is secured by a screw 12.

Pin 9 is shown as fixed in FIG. 4. Alternately, and as shown in FIG. 5, the fin may be mounted for pivoting movement on a vertical pin 13. The pivoting type of fin will assist in resisting propeller torque reaction.

Fin 9 prevents galvanic corrosion of member 6 by being electrically connected thereto and by being constructed of a metal which is dissimilar to and substantially less noble in the electromotive series than member 6. For example, if the intake member is made of iron or steel, fin or anode 9 should be made of aluminum, zinc or magnesium, in increasing order of preference.

The electrolytic salt water will create a galvanic cell, with fin 9 acting as the anode and being sacrificed to protect member 6, which becomes the cathode. Fin 9, being a removable component, can easily be replaced once it has corroded sufficiently to lose its usefulness.

If desired an additional anode 13 may be secured inside member 6 adjacent openings 7, as shown in FIG. 2, and provide additional electrolytic protection to maintain openings 7 free of corrosion products.

The invention provides a novel means for preventing corrosion and clogging of the water intake structure of an outboard mounted marine propulsion device. The cathodic protection provided prevents a gradual reduction of water intake and the resultant loss of engine efficiency due to overheating.

Various modes of carrying out the invention are contemplated as being within the scope of the following claim-s particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. In an outboard motor having a water-cooled engine and an underwater gear housing carrying a propeller, a metallic water intake in said housing above and to the rear of said propeller and having a plurality of relatively small inlet openings facing said propeller for passage of water therethrough to cool the engine, and a removable metallic fin mounted on said housing adjacent and rearwardly of the sad intake with said fin being constructed of a metal of less noble characteristics than said intake to thereby prevent corrosion and clogging of the said intake when the latter is submerged in water and resultant overheating of the engine.

2. The construction of claim 1 and an anode of metal secured inside said housing adjacent said intake openings and in the path of the water entering through said water intake.

3. In an outboard motor having a water cooled engine, an underwater metallic gear housing carrying a propeller, a Water intake in said housing connected by a passage to the engine cooling system to supply Water thereto, said intake having a plurality of small intake openings that tend to clog from corrosion products, and an anode of metal less noble than the metal of said intake secured inside said housing adjacent to said intake and disposed in the path of the water entering through said intake.

References Cited in the file of this patent UNITED STATES PATENTS 1,900,011 Durham Mar. 7, 1933 1,980,685 Johnson Nov. 13, 1934 2,652,802 Carlson Sept. 22, 1953 

